Commercial and industrial storage tanks are widely used for the bulk storing of liquids. The storage tanks are typically made of steel or fiberglass reinforced resin. The walls of the tanks range up to an inch thick depending on the tank's capacity. Such a thickness and resultant strength is needed because of the tremendous amount of forces exerted on the walls of the tank by the weight of the stored liquid as well as ground movements. Complete tank failure can occur by forces being so great as to buckle a wall. Since many of the liquids commonly stored are highly corrosive and/or are flammable, they pose a significant health and safety hazard if not properly contained.
Tanks made from fiberglass reinforced resinous material are extensively used. Different methods are used for making these tanks. One commercial method of making tanks from fiberglass reinforced resinous material utilizes a removable split half-mold with shapes for forming the support ribs and end cap along with the main body. After fiberglass and resinous material are applied to the mold and cured, the mold is removed. Next, the interior portions of the rib areas are filled with a filler material or bridged over with a cardboard insert and fiberglass/resin applied so as to form a substantially smooth tank interior. The weakest part of such a tank is in the body portion or non-ribbed area of the tank. Any failure in this area will likely lead to a sudden large leak.
Recent concerns about leaked tanks have increased the need for an efficient and economical manner of building a reliable storage tank system. In accord with this need, there has now been discovered a method whereby strengthened storage tanks are built in an efficient, yet economical manner.